Role of IL-4 and IL-13 in Schistosoma-induced pulmonary hypertension (LB780)

Background: Schistosomiasis-associated pulmonary arterial hypertension (PAH) occurs in the context of Th2 inflammation, which is induced by IL-4 and IL-13. We had previously observed that TGF-β signaling is necessary for Schistosoma-induced pulmonary hypertension (PH) in the mouse. We hypothesized that IL-4 and IL-13 were necessary for the TGF-β-induced pulmonary vascular disease induced by Schistosoma. Methods: Wild type, IL-13YFP, IL-4GFP, IL-4-/-, IL-13-/- and IL-4-/-IL-13-/- mice (N=5-17 per group) were intraperitoneally (IP) sensitized with 175 S. mansoni eggs/gram body weight, two weeks later intravenously (IV) challenged via tail vein with the same dose of eggs, and one week thereafter underwent right ventricular catheterization followed by quantitative histologic and protein analysis, or lung digestion and flow cytometry. Lung tissue from patients who died of schistosomiasis-associated PAH was studied by immunostaining. Results: The lungs of patients with schistosomiasis-associated PAH and mice wi...